NATURE'S OWN SEAPLANES — HUBBS 341 



These claims have for the most part been made by others than 

 trained naturalists or b}' iaborator}^ zoologists equally untrained in 

 field observation. Such accurate, trained observers as Moseley, Jor- 

 dan, Gilbert, and many others have been unable to detect any move- 

 ment of the fish's main planes while it flew throuirh the air. Neither 

 for the California flying fish nor for the several species I studied on 

 the opposite side of the Pacific could I observe any wing movement 

 which by any reasoning could be thought to sustain the fish in the 

 air. The vibration of the pectoral tips tlirough a small amplitude 

 during the taxi, assuredly the mere consequence of the vigorous 

 sweeping of the tail, as already stressed, ceases instantaneously as the 

 caudal fin rises clear of the water. And these fins remain stretched 

 taut and firm until the moment when the fish either dives into the 

 sea or until its tail fin dips in the water and resumes the violent 

 sculling, which immediately induces a renewal of the hazy appear- 

 ance of the fin tips. The frequent naive claims that this secondary 

 vibration becomes apparent only when the fish is fatigued and that 

 the wing vibration wliile the fish had been in the air was too rapid 

 to be seen by the eye are at once refuted by the fact that the wing 

 appears as a single blade, whereas if it had been moved too fast to 

 follow, it would have appeared double like a humming bird's wing, 

 with one image at each end of the stroke. 



That there is absolutely no vibration of the outstretched pectoral 

 fins while the fish is in the air is clearly observable, even without the 

 aid of field glasses. Whenever a fish happens to fly directly away 

 from the observer, a condition which would make easily evident any 

 up-and-down movement, the edges of the planes always stand out 

 clear like knife's edges, without a trace of doubling or of a blur, 

 even when the fish flies into a high wind (which some have said 

 causes a vibration of the fin). It has been with full certainty also 

 that I have observed the rigidity of the planes hundreds of times as 

 I have looked down through field glasses at flying fishes close to 

 the boat. When the pectoral fins are blackish, and, better yet, when 

 they are marked with an oblique yellow band or by black blotches, 

 it is especially easy to appreciate that these fins remain motionless 

 in relation to the fish. 



The anatomical researches of Mobius (1878), Ahlborn (1895), 

 llidewood (1913), and others have disclosed no muscular or other 

 modification sufficient to make one suspect that these fishes can flap 

 their wings sufficiently to maintain their heavy bodies in the air. 



The pelvic fins, the lower or posterior planes, likewise are never 

 seen to vibrate. They remain folded as the caudal beats the surface 

 and thus do not participate in the slight vibration of the fin tips 

 induced by this tail movement. Especially when the pelvics are 



